Miami International Airport will close one of its terminals early this weekend as double the usual number of Transportation Security Administration officers, working unpaid in the partial government shutdown, called in sick.

The TSA workers are among the some 420,000 federal employees deemed essential who are working without pay. Amid the shutdown, which began on Dec. 22 and is now the longest ever, TSA officers missed their first paycheck on Friday.

The shifts show how the impact from the shutdown, the result of an impasse between President Donald Trump and lawmakers over funding for a barrier along the southern U.S. border, are impacting aviation. The shutdown has stalled the required federal approvals for new jets and routes, as well as certifications for new mechanics and other industry employees.

The agency acknowledged that unscheduled absences of the 51,000 TSA officers have been on the rise, but said “security standards remain uncompromised at our nation’s airports.” About 5.6 percent of officers called out sick on Saturday, up from 3.3 percent a year ago, spokesman Michael Bilello said.

The TSA considers a normal wait time on security line 30 minutes or less. At Miami International Airport, McCarren International Airport (which serves Las Vegas) and Fort Lauderdale-Hollywood International Airport, maximum wait times were 29 minutes, Bilello said. Others around the country were lower, and the impact to air travelers has so far been minimal.

“We usually see 30-40 TSA call-outs per day, but that has doubled in the last few days,” Greg Chin, spokesman for Miami International Airport, told CNBC in an email. He said that the airport has about 700 TSA workers scheduled to work daily.

Starting Saturday, flights scheduled to fly from Terminals G after 1 p.m. through the same time on Sunday and Monday, will be relocated to Terminals F or H. The change is a “precautionary measure and to better utilize the decreased staffing,” Chin said.

United Airlines will use other gates for flights that were scheduled to depart from Terminal G, and is telling travelers to arrive at the airport early and to check for changes, a spokeswoman said.

TSA Administrator David Pekoske late Friday said the screeners would receive $500 and be paid for Dec. 22, the day the shutdown began.

The aviation world has been among the most vocal industries demanding an end to the shutdown, complaining about lost wages and potential economic damage from the impasse.

“As the partial government shutdown continues, the human and economic consequences are increasing and doing greater harm,” aviation industry members wrote in a letter to President Donald Trump, House Speaker Nancy Pelosi and Senate Majority Leader Mitch McConnell.

Airlines need Federal Aviation Administration inspectors’ approval to debut new aircraft. The FAA on Thursday said it was prepared to call up its inspectors and engineers for critical safety functions, if needed, Still, the shutdown has raised questions about air carriers’ ability to follow through with scheduled events.